An upgrade to the new Wilwood brakes is available at no cost. Some users of the new brakes have had issues with them; they sometimes required a quick pump after a long straight. The new spring eliminates any knock-back or pumping of the brakes. Drivers that have the new springs are pleased with the brake performance, and the knock-back is eliminated. The new springs are included with new brakes, and they are free for people that already have the Wilwood brakes. Just contact your CSR if you need the spring upgrade. Bruce http://www.accelracetek.com